No description available.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: W.-P. Huang Includes bibliographical references (leaves 124-136).

Η εργασία αυτή εχεις ως αντικείμενο την μελέτη και την κατασκευή ενός μετατροπέα συντονισμού για την οδήγηση ενός πιεζοηλεκτρικού κινητήρα οδεύοντος κύματος τύπου Ultrasonic. Αρχικά γίνεται μια θεωρητική αναφορά στους πιεζοηλεκτικούς κινητήρες και τους ηλεκτρονικούς μετατροπείς ισχύος ενώ ακολουθεί η προσομοίωση του μετατροπέα στο Pspice. Ακολούθως αναλύεται η διαδικασία της κατασκευής και ακολουθούν τα πειραματικά αποτελέσματα καθώς και τα συμπεράσματα που λάβαμε. / In this thesis someone can find about designing and manufacturing a resonant inverter in order to control a piezoelectric traveling wave ultrasonic motor. In the first chapters someone can read about the piezoelectric phenomenon, piezoelectric motors and about electronic converters which control the velocity of motors. Next there is a presentation of the Pspice simulation model and results. Furthermore there is the manufacturing procedure of the inverter and at the end there are the results and conclusion of the thesis.

O sistema de FitzHugh-Nagumo possui um tipo especial de solução chamadas ondas viajantes, que são da forma &micro(x,t)=&oslash(x+ct) e w(x,t)=&#1137(x+ct) e além disso sabe-se que ela é estável. Tem-se o interesse de obter uma caracterização de seu perfil (&oslash,&#1137) e sua velocidade de propagação c. Fazendo uma mudança de variáveis, transformamos tal problema em encontrar equilíbrios de uma equação não local. Esta equação não local possui uma onda viajante de velocidade zero cujo perfil é o mesmo da equação original e, com esta equação, é possível aproximar, ao mesmo tempo, o perfil e a velocidade da onda viajante. Como a intenção é usar métodos numéricos para aproximar tais soluções, o problema não local foi analisado em um intervalo limitado verificando a existência e algumas propriedades espectrais em domínios limitados. / The FitzHugh-Nagumo systems have a special kind of solution named traveling wave, which has a form &micro(x,t)=&oslash(x+ct) and w(x,t)=&#1137(x+ct) and furthermore it is a stable solution. It is our interest to obtain a characterization of its profile (&oslash,&#1137) and speed of propagation c. Changing variables, we transform the problem of finding these solutions in the problem of finding an equilibria in a nonlocal equation. This nonlocal equation has a traveling wave with zero speed whose profile is the same of the original equation, and the nonlocal equation is used to approximate the profile and speed of the traveling wave at the same time. To use numerical methods for approximating such solutions, the nonlocal problem was analyzed in a finite interval to check that the existence and some spectral properties on bounded domains.

In this thesis we employ two recent analytical approaches to investigate the possible classes of traveling wave solutions of some members of recently derived integrable family of generalized Camassa-Holm (GCH) equations. In the first part, a novel application of phase-plane analysis is employed to analyze the singular traveling wave equations of four GCH equations, i.e. the possible non-smooth peakon, cuspon and compacton solutions. Two of the GCH equations do no support singular traveling waves. We generalize an existing theorem to establish the existence of peakon solutions of the third GCH equation. This equation is found to also support four segmented, non-smooth M-wave solutions. While the fourth supports both solitary (peakon) and periodic (cuspon) cusp waves in different parameter regimes. In the second part of the thesis, smooth traveling waves of the four GCH equations are considered. Here, we use a recent technique to derive convergent multi-infinite series solutions for the homoclinic and heteroclinic orbits of their traveling-wave equations, corresponding to pulse and front (kink or shock) solutions respectively of the original PDEs. Unlike the majority of unaccelerated convergent series, high accuracy is attained with relatively few terms. Of course, the convergence rate is not comparable to typical asymptotic series. However, asymptotic solutions for global behavior along a full homoclinic/heteroclinic orbit are currently not available.

We study a system of semilinear hyperbolic PDEs which arises as a continuum approximation of the discrete nonlinear dimer array model of SSH type of Hadad, Vitelli and Alú in [1]. We classify the system’s traveling waves, and study their stability properties. We focus on pulse solutions (solitons) on a nontrivial background and moving domain wall solutions (kinks and antikinks), corresponding to heteroclinic orbits for a reduced two-dimensional dynamical system. We further present analytical results on: nonlinear stability and spectral stability of supersonic pulses, and the spectral stability of moving domain walls. Our result for nonlinear stability is expressed in terms of appropriately weighted ?1-norms of the perturbation, which captures the phenomenon of convective stabilization; as time advances, the traveling wave “outruns” the growing disturbance excited by an initial perturbation. We use our analytical results to interpret phenomena observed in numerical simulations. The results for (linear) spectral stability are studied in appropriately-weighted ?2-norms.

No description available.

<p>The development of silicon photonics, driven by the increasing demand for bandwidth from data centre applications, is receiving growing attention. As a result of the indirect bandgap of Si material, it is more practical to heterogeneously incorporate the laser source than fabricate directly on Si. Of all the approaches, an external cavity laser (ECL) approach which consists of III-V gain material and Si photonic integrated circuit (SiPIC), is a flexible and cost effective solution. This thesis captures theoretical and experimental work on the design of SiPIC ECLs. In addition, a four wavelength laser source using an SiPIC ECL scheme is proposed and studied.</p> <p>The theoretical tool is first introduced on the traveling wave model (TWM) and it is numerically solved with FDTD in Matlab. A digital filter approach is used to describe the feedback from an SiPIC external cavity, where the phase delay of the digital filter is investigated and utilized to set the cavity length.</p> <p>The III-V gain chip and SiPIC are then examined separately for their characterization, along with the coupling and feedback requirements in an ECL design.</p> <p>Lastly, experiments are conducted to demonstrate the feasibility of four wavelength ECLs and SiPIC ECLs.</p> / Master of Applied Science (MASc)

Este trabalho apresenta o desenvolvimento de uma plataforma para o estudo teórico e experimental de dispositivos amplificadores de micro-ondas do tipo válvula de ondas progressivas (TWT). A plataforma é composta por um modelo matemático e uma bancada de testes. O modelo matemático descreve a TWT como uma linha de transmissão acoplada a um feixe eletrônico unidimensional, onde as forças de carga espacial AC e DC são calculadas auto consistentemente, eliminando-se a necessidade de um cálculo separado para o fator de redução de carga espacial. O modelo matemático deu origem a dois códigos para a simulação da TWT. Ambos foram comparados com resultados experimentais e teóricos disponíveis na literatura especializada para uma pré-validação. O nível de concordância entre os presentes resultados e aqueles de referência foi acima de 90%, o que atendeu as expectativas de exatidão do modelo, tendo em vista que nem todos os parâmetros de entrada estavam disponíveis na referência. A bancada de testes construída é composta por uma TWT com banda de operação de 6,0 a 18 GHz e potência saturada máxima em torno de 55 dBm (316 W) em 13 GHz, um circuito de polarização para a mesma e a instrumentação necessária para a realização das medidas pertinentes aos amplificadores de potência. A TWT em questão foi caracterizada segundo seu comportamento mono-sinal e multi-sinal. As curvas de ganho e potência foram obtidas em função da frequência utilizando a voltagem de aceleração do feixe eletrônico e a potência de entrada como parâmetros. As curvas de transferência de potência, de fase e compressão de ganho foram obtidas para frequências escolhidas ao longo da banda, tendo novamente a voltagem de aceleração como parâmetro. Adicionalmente, a produção de produtos de intermodulação de terceira ordem foi caracterizada no ponto de 1 dB de compressão de ganho ao longo da banda analisada. Um teste de linearização por injeção de sinais, que estava previsto no plano de trabalho, não apresentou o desempenho esperado devido a problemas no funcionamento do circuito linearizador. Esses problemas foram analisados e listou-se uma série de passos para saná-los. / This work deals with the development of a platform for theoretical and experimental investigations of microwave amplifiers devices of the type traveling-wave tube (TWT). The platform consists of a mathematical model and a test bench. The mathematical model describes the TWT as a transmission line coupled to a onedimensional electron beam, in which the AC and DC space charge forces are calculated self-consistently, eliminating the need for a separate calculation for the space charge reduction factor. The mathematical model gave rise to two codes for the simulation of TWTs. Both codes were validated against experimental and theoretical results available in the literature. The overall level of agreement between the present results and those from the reference was above 90%, which was considered satisfactory since not all input parameters were available in the reference. The test bench consists of a wideband TWT operating from 6.0 to 18 GHz and maximum saturated power around 55 dBm (316 W) at 13 GHz, a biasing circuit, and the instrumentation needed to perform the relevant measurements to the power amplifier. The TWT in question was characterized according to its mono-signal and multi-signal behavior. The gain and power curves were obtained as a function of the frequency using the beam voltage and the input power as parameters. The curves of power transfer, phase transfer and gain compression were obtained for selected frequencies along the operating band, again, using the beam voltage as a parameter. Furthermore, the production of third-order intermodulation products was measured at the 1 dB gain compression point over the band analyzed. A linearization test applying the signal injection technique, which was part of the initial work plan, presented inadequate performance due to problems in the linearizer circuit operation. These problems were analyzed and a guide to solve them was provided.

Este trabalho apresenta o desenvolvimento de uma plataforma para o estudo teórico e experimental de dispositivos amplificadores de micro-ondas do tipo válvula de ondas progressivas (TWT). A plataforma é composta por um modelo matemático e uma bancada de testes. O modelo matemático descreve a TWT como uma linha de transmissão acoplada a um feixe eletrônico unidimensional, onde as forças de carga espacial AC e DC são calculadas auto consistentemente, eliminando-se a necessidade de um cálculo separado para o fator de redução de carga espacial. O modelo matemático deu origem a dois códigos para a simulação da TWT. Ambos foram comparados com resultados experimentais e teóricos disponíveis na literatura especializada para uma pré-validação. O nível de concordância entre os presentes resultados e aqueles de referência foi acima de 90%, o que atendeu as expectativas de exatidão do modelo, tendo em vista que nem todos os parâmetros de entrada estavam disponíveis na referência. A bancada de testes construída é composta por uma TWT com banda de operação de 6,0 a 18 GHz e potência saturada máxima em torno de 55 dBm (316 W) em 13 GHz, um circuito de polarização para a mesma e a instrumentação necessária para a realização das medidas pertinentes aos amplificadores de potência. A TWT em questão foi caracterizada segundo seu comportamento mono-sinal e multi-sinal. As curvas de ganho e potência foram obtidas em função da frequência utilizando a voltagem de aceleração do feixe eletrônico e a potência de entrada como parâmetros. As curvas de transferência de potência, de fase e compressão de ganho foram obtidas para frequências escolhidas ao longo da banda, tendo novamente a voltagem de aceleração como parâmetro. Adicionalmente, a produção de produtos de intermodulação de terceira ordem foi caracterizada no ponto de 1 dB de compressão de ganho ao longo da banda analisada. Um teste de linearização por injeção de sinais, que estava previsto no plano de trabalho, não apresentou o desempenho esperado devido a problemas no funcionamento do circuito linearizador. Esses problemas foram analisados e listou-se uma série de passos para saná-los. / This work deals with the development of a platform for theoretical and experimental investigations of microwave amplifiers devices of the type traveling-wave tube (TWT). The platform consists of a mathematical model and a test bench. The mathematical model describes the TWT as a transmission line coupled to a onedimensional electron beam, in which the AC and DC space charge forces are calculated self-consistently, eliminating the need for a separate calculation for the space charge reduction factor. The mathematical model gave rise to two codes for the simulation of TWTs. Both codes were validated against experimental and theoretical results available in the literature. The overall level of agreement between the present results and those from the reference was above 90%, which was considered satisfactory since not all input parameters were available in the reference. The test bench consists of a wideband TWT operating from 6.0 to 18 GHz and maximum saturated power around 55 dBm (316 W) at 13 GHz, a biasing circuit, and the instrumentation needed to perform the relevant measurements to the power amplifier. The TWT in question was characterized according to its mono-signal and multi-signal behavior. The gain and power curves were obtained as a function of the frequency using the beam voltage and the input power as parameters. The curves of power transfer, phase transfer and gain compression were obtained for selected frequencies along the operating band, again, using the beam voltage as a parameter. Furthermore, the production of third-order intermodulation products was measured at the 1 dB gain compression point over the band analyzed. A linearization test applying the signal injection technique, which was part of the initial work plan, presented inadequate performance due to problems in the linearizer circuit operation. These problems were analyzed and a guide to solve them was provided.